Esters of adamantane-1-acetic acid

ABSTRACT

A compound of the formula   WHEREIN R is selected from the group of hydrocarbon radicals having 4 to 20 carbon atoms consisting of (a) linear and branchchain alkyls and alkenyls, and (b) monocyclic and polycyclic cycloalkyls and cycloalkenyls; and R&#39;&#39; is H or alkyl having 1 to 4 carbon atoms, is prepared by reacting adamatane-1-acetic acid, or its alkyl derivatives, with a monohydric alcohol (ROH) in the presence of esterification catalyst. The compounds are useful as oiling agents for synthetic fibers and as synthetic lubricating oil bases.

United States Patent [191 Inamoto et al.

[451 June 18,1974

[ ESTERS OF ADAMANTANE-l-ACETIC ACID [75] Inventors: Yoshiaki Inamoto;Hirokazu Nakayama, both of Wakayama; Hidetsugu Takenaka, Arita;Yoshitomo Kimura, Wakayama, all

of Japan [73] Assignee: Kao Soap Co., Ltd., Tokyo, Japan [22] Filed:July 23, 1971 21 Appl. No.: 165,752

[30] Foreign Application Priority Data July 31, 1970 Japan 45-67203 [52]US. Cl. 260/468 G, 252/57 [51] Int. Cl. C07c 69/74 [58] Field of Search200/468 G, 468 CA [56] References Cited UNlTED STATES PATENTS 7/1971Szinai et a1. 260/617 OTHER PUBLICATIONS Stepanov et al., Zh. Obsch.Khimii, 34 579 (1964) Primary Examiner-Lorraine A. Weinberger AssistantExaminerRobert Gerstl Attorney, Agent, or Firm-Woodhams, Blanchard andFlynn ABSTRACT A compound of the formula CllzCOOR 4 are useful as oilingagents for synthetic fibers and as synthetic lubricating oilbases.

2 Claims, No Drawings ESTERS OF ADAMANTANE-l-ACETIC ACID BACKGROUND OFTHE INVENTION 1. FIELD OF THE INVENTION This invention relates to aprocess for preparing esters of adamantane-l-acetic acid. Moreparticularly, it relates to a process for preparing esters ofadamantanel-acetic acid and alkyladamantane-l-acetic acid with higheralcohols having from 4 to carbon atoms.

2. DESCRIPTION OF THE PRIOR ART Among the esters of adamantane-l-aceticacid and ring-substituted alkyl derivatives thereof, only a few methylesters such as methyl 3-methylaclamantyll-acetate, methyl 3,S-dimethyladamantyll -acetate, etc. (K. Bott, Ber. I01, 564 1968)) havebeen synthesized hitherto but higher esters with alcohols having morethan four carbon atoms, have not been known.

SUMMARY OF THE INVENTION According to the invention, there is provided acompound of the formula LCHZCOOR wherein R is selected from the group ofhydrocarbon radicals having 4 to 20 carbon atoms consisting of (a)linear and branch-chain alkyls and alkenyls, and (b) monocyclic andpolycyclic cycloalkyls and cycloalkenyls; and R is H or alkyl having 1to 4 carbon atoms.

We have found that adamantanel -acetic acid and its ring-substitutedalkyl derivatives can be esterified with various higher alcoholsaccording to known methods. Thus, the present invention provides amethod of preparing the novel esters by the reaction ofadamantanel-acetic acid, or ring-substituted derivatives thereof, withstraight-chain or branched-chain noncyclic or monoor polycyclic alkanolsor alkenols in the presence of an acid, neutral or basic catalyst.

These esters contain the adamantane ring which renders the molecule highthermal stability as well as providing many characteristic advantageouspropertiesnot encountered in usual fatty esters. Therefore, these novelesters are very useful as components of oiling agents for syntheticfibers, as synthetic lubricating oil bases, particularly for airplaneusage, and for many other purposes.

The object of the present invention can be achieved by heatingadamantane-l-acetic acid or ringsubstituted alkyl derivatives thereofwith the said higher alcohols in the presence of esterificationcatalysts. The effective catalysts to be used in the present reactioninclude acid catalysts such as sulfuric acid, aliphatic and aromaticsulfonic acids, boron trifluoride and the like, neutral or alkalinecatalysts such as oxides or hydroxides of alkali metals, alkaline earthmetals, zinc, cadmium, tin, lead, antimony, bismuth and the like, allthe other known esterification catalysts being included.

Examples of the ring-substituted derivatives of adamantane-l-acetic acidare 3-methyl-, 3,5-dimethyl-, 3,5,7-trimethyl-, 3-methyl-5-ethyl-,3,5-dimethyl-7- ethyl-, and 3-n-propyl-adamantyl-l-acetic acid. Thereactivities of substituted derivatives are quite similar to that of theunsubstituted adamantane-l-acetic acid in the esterification reaction ofthe present invention.

The said higher alcohols having 4 to 20 carbon atoms includestraight-chain alkanols such as n-butyl alcohol, n-amyl alcohol, n-hexylalcohol, n-octyl alcohol, lauryl alcohol, myristyl alcohol and stearylalcohol; branched chain alkanols such as i-butyl alcohol, i-amylalcohol, 2-ethylhexanol-l 2-methyl-dodecanol-1 straightchain alkenolssuch as crotyl alcohol, oleyl alcohol, linoleyl alcohol and the like;branched-chain alkenols such as methallyl alcohol and the like;monocyclic alkanols such as cyclohe'xanol, methylcyclohexanols,cyclohexyl carbinol; monocyclic unsaturated alcohols such as2-cycl0hexenol; saturated polycyclic alcohols such as 2-decalol,l-hydroxy-adamantane, 2-exohydroxy-exo-trimethylenenorbornane and thelike; unsaturated polycyclic alcohols such as 2-exo-hydroxy-2,3-dihydro-exo-dicyclopentadiene, etc.

Although it is usual practice to use either the acid or the alcohol inan amount in excess of the stoichiometric ratio to reduce the reactiontime in the esterification reaction of the present invention, use ofstoichiometric amounts, of course, leads smoothly to the desiredproducts.

The amount of the catalyst to be used in the present esterificationreaction is generally in the range of 0.0001 to 0.1 equivalent,preferably 0.0005 to 0.005 equivalent, per mole of the startingcarboxylic acid.

By using a suitable catalyst selected from those described above in theamount indicated, the present esterification reaction can be completedwithin 24 hours.

The reaction temperature used in the esterification reaction accordingto the invention is substantially the same as those used in theesterification of ordinary aliphatic carboxylic acids, namely, in therange of 30 to 300 C, preferably 50 to 270 C.

The water produced during the esterification reaction can be removedfrom the reaction system by any of the known methods such asdistillation under reduced pressure, removal by passing an inert gasthrough the reaction mixture, or use of an azeotropic dehydrating agent.It is preferable in the present process to use an excess of acid ratherthan an excess of the alcohol if the esters of high boiling pointalcohols are to be prepared. Use of excess acid, however, causes thetrouble of sublimation of the acid. This is prevented very effectivelyby the use of an azeotropic dehydration solvent such as n-hexane,cyclohexane, benzene, toluene, xylene and the like.

The present invention is further illustrated by the following examples,where the parts are by weight unless otherwise noted, and all meltingpoints are uncorrected.

EXAMPLE 1 Preparation of butyl ester of adamantane-l-acetic acid (I)(R'=I-I, R=C H In a reaction flask equipped with the water separatordescribed in Organic Syntheses, Coll. Vol. 3, p. 382, a mixture of 15.45parts of adamantane-l-acetic acid, 59.30 parts of n-butyl alcohol and3.74 parts of ptoluene sulfonic acid crystals was refluxed at 120 to 122C for 24 hours while separating the water produced during the reaction.

After cooling, the reaction mixture was washed successively with coldwater, then with saturated sodium bicarbonate solution (until thewashings became distinctly alkaline) and then with cold water, driedover anhydrous potassium carbonate and fractionated under reducedpressure.

The fraction boiling at 98100 C (0.06 mm) was collected, giving 14.5parts (yield 73 percent) of colorless liquid of adamantyl-l-butylacetate (1), n 1.4867.

ANALYSlS Found: C, 75.8; H, 10.1; 0, 12.8 percent. Calculated for C H O-C, 76.75; H, 10.47; 0,

12.78 percent. 1R spectrum (liquid film, cm") 1,735 (s): we 0, ester1,260 (s), 1,140 (s): vc-o-c, ester NMR spectrum (CCl, solution, TMS asinternal standard, r)

7.98.2 (undlssolved resonance) (5H) :tertiary Hs on the adamantane ringand AdCH 2- 8.3 (s) 8.28.5 (undissolved resonance, 12H) :secondary Hs onthe adamantane ring 8.5-8.0 (complex m, 4H) 0 CII2(CH1)2CH3 9.07 (t,J=7H,, 3H) :CIi3

Mass spectrum (m/e (relative intensity)) 250 (2.2) (parent peak), 195(9.7), 177 (4.9), 148 (8.2), 135 (100.0)

EXAMPLE 2 Preparation of Z-ethylhexyl ester of adamantane-l- Nineteenand four tenths (19.4) parts of adamantane-l-aceticacid, 16.93 parts of2-ethylhexanol, 0.1 1 part of zinc oxide and 5.0 parts of xylene wereplaced in the reaction vessel as described in Example 1, and the mixturewas heated to 210 C for 6 hours with stirring while separating the waterformed during the reaction.

After cooling to about 50 C, 100 parts by volume of water at 50 C and100 parts by volume of xylene were added to the reaction mixture, andthe resulting mixture was stirred at 50-60 C for 30 minutes. The xylenelayer was separated, washed with cold saturated solution of sodiumbicarbonate until the washings became alkaline, followed by washing withcold water until neutral, dried over anhydrous sodium sulfate and thanfractionated in vacuo.

The fraction boiling at 133135 C (0.09 mm) gave 20.47 parts (yield 68percent) of(11) as a colorless liquid, r1 1.4840.

ANALYSIS Found: C, 78.2; H, 11.0; 0, 10.5 percent. Calculated for C H OC, 78.38; H, 11.18; 0,

10.44 percent. IR spectrum (liquid film, cm") 1,735 (s): we o, ester1,260 (s), l,140(s): vc-o-c, ester NMR spectrum (CC1,, TMS as internalstandard; 1')

6.12 (d. J=7H,, 2H) :C OOCE CH 7.88.2 (undissolved resonance) 1-(511):tane ring and AdCQ C O 0* 8.05 (s) 8.28.5 (undissolved resonance, 12H)secondary Hs on the adamantane 9.13 (t, J=711,, 6H) :terminal Clis Massspectrum (m/e (relative intensity)) 306 (0.3) (parent peak), 195 (7.9),193 (6.2), 177

EXAMPLE 3 Preparation of lauryl ester of adamantane-l-acetic acid (111)(R'=l-l, R=C,- ,H

A reaction mixture comprising 15.54 parts of adamantane-l-acetic acid,18.63 parts of lauryl alcohol, 0.10 part of stannous oxide and 8.0 partsby volume of xylene was stirred at 210-220 C for 10 hours in thereaction flask as described in Example 1.

The reaction mixture was diluted with xylene as in the case of Example2, treated with warm water. and washed with sodium bicarbonate andwater. dried over anhydrous sodium bicarbonate and then fractionated invacuo.

The fraction boiling at 182185 C (0.055 mm) was collected to give 21.6parts percent yield) of (111) as colorless liquid, n 1.4789.

ANALYSlS 6.02 (t, J=7H,, 2H):OC@

7.8-8.2 (uudissolved resonance)- 8.2-8.5 (undissolved resonance 12H):secondary H's on the adamant-aha ring tertiary Hs on the adamantane ringand AdCQCOO Mass spectrum (m/e (relative intensity)) tertiary H's on theadaman- 362 (0.8) (Parent peak), 213 (2.0), 195 (27.3), 193

EXAMPLE 4 Preparation of stearyl ester of adamantane-l-acetic acid (IV)(R'=H, R=C H A mixture comprising 15.54 parts of adamantane-laceticacid, 27.03 parts of stearyl alcohol, 0.2 parts of stannous oxide and9.0 parts by volume of xylene was stirred at 210230 C for hours in thesame apparatus as described in Example 1.

The reaction mixture was treated in the same way as in Example 2.Evaporation of xylene from the dried xy lene solution gave a viscousresidue which solidified on standing in a refrigerator overnight.

Recrystallization twice from acetone gave 19.9 parts (yield 56 percent)of colorless crystals of pure (1V), m.p. 30.5-32 C.

ANALYSIS Found: C, 80.9; H, 12.3; 0, 6.9 percent. Calculated for C H OC, 80.65; H, 12.18; 0, 7.19

percent. IR spectrum (KBr, cm) 1,735 (s): 110 0, ester 1,260 (s), 1,140(s): vc-o-c, ester 725 (m): p-(CH long-chain alkyl (polymethylene). NMRspectrum (CCl, solution, TMS as internal standard, T)

(undissolved resonance) tertiary H's on the adamantane 8 02 (5) I ringand AdCgzCOO- 8.2-8.5 (undissolved resonance, 12H): secondary 11s on theadamantane nng Mass spectrum (m/e (relative intensity)) 446 (1.5)(parent peak), 297 (2.2), 252 (5.2), 195

EXAMPLE 5 pale yellow viscous oil, n 1.4670, as the distillationresidue.

Saponification value.

Found: 128.2; calculated, 126.2.

Iodine value.

Found: 53.7; calculated, 57.6.

Acid value.

Found: 0.43; calculated, 0.

Hydroxyl value.

Found: 0.76; calculated, 0.

EXAMPLE 6 Preparation of cyclohexyl ester of adamantane-l-acetic acid(VI) (R'=H, R=C H A mixture comprising 15 .54 parts of adamantane-1-acetic acid, 80.12 parts of cyclohexanol, and 0.49 part of zinc oxidewas stirred at 170 C for 22 hours.

ANALYSIS Found: C, 77.9; H, 10.2; 0, 11.3 percent. Calculated for C,,,H,,O C, 78.21; H, 10.21; 0, 11.58 percent. 1R spectrum (liquid film, cm)

1,730 (s): we 0, ester 1,260 (s), 1,135 (s): vc-o-c, ester NMR spectrum(CC1 solution, TMS as internal standard, 'r)

7.8-8.2 (undissolved resonance) tertiary H's on the adamantane ring andAdCH2COO 8.2 8.5 (undissolved resonance, 12H): secondary H's on theadamantane ring 8.5 9.0 (complex m): cyclohexane ring Hs Mass spectrum(m/e (relative intensity)) 276 (0.7) (parent peak), (77.5), 193 (5.1),177

EXAMPLE 7 Preparation of exo-trimethylene-norbornyl-2-exo ester ofadamantane-l-acetic acid (V11) (R'=H, R=

A mixture comprising 19.40 parts of adamantane-1- acetic acid, 19.80parts of 2-exo-hydroxy-exotrimethylenenorbornane, 012 part of zincoxide, and 10 parts of xylene was stirred at a temperature below 230 for8 hours.

The reaction mixture was treated in the same way as in Example 2, andthe fractionation of the xylene solution gave 21.40 parts (65 percentyield) of pure (VII), boiling at 172173 C (0.085 mm), m, 1.5250.

ANALYSIS Found: C, 80.4; H, 9.7; O, 9.6 percent.

Calculated for C H O C, 80.44; H, 9.83; O, 9.74 percent. 1R spectrum(liquid film, cm") 1,735 (s): we 0, ester 1,260 (s), 1,140 (s): vc-o-c,ester. NMR spectrum (CCI, solution, TMS as internal standard, r)

4.45 4.70 (complex m):

7.8 9.3 (complex m, with peaks at 8.05 (broad S), 8.13 (s), 8.43 (broad5)): adamantane ring H's and trimethylenenorbornane ring Hs. Massspectrum: (m/e (relative intensity)) 328 (1.8) (parent peak). 300 (3.0},195 (2.1), 193

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

l. A compound of the fonnula CHZCOOR crncooa wherein R is selected fromthe group consisting of crotyl. oleyl, linoleyl and methallyl; and R isH or alkyl having 1 to 4 carbon atoms.

2. A compound of the formula